Can acid supplements replace copper in pig diets?

With the long-awaited changes to the copper levels allowed in animal feeds now officially in effect, finding alternatives to copper is higher on the industry agenda than ever before

The function of copper in pig diets

Copper is required for the maintenance of physiological processes including the following:

Along with iron, copper is required to allow red blood cells to form normally and deficiencies in this metal can lead to anaemia.

Copper optimises nutrient absorption and digestibility.

It functions as an antioxidant to manage oxidative stress.

It contributes to collagen development for tissue and bone health.

Copper also suppresses bacterial growth. Removing copper from young pig diets results in bacterial enteritis and reduced growth, most likely associated with the sudden multiplication of pathogenic bacteria.

The new copper feed additive regulations

Inclusion levels are measured in mg/kg of complete feed with a moisture level of 12 percent.

For piglets a total of 150mg/kg complete feed is allowable up to four weeks after weaning, a decrease from the 170mg/kg previously permitted.

For piglets from the fifth week after weaning up to the eighth week, a total of 100 mg/kg complete feed is allowable.

The document issued by the EU outlines that a "transitional period for interested parties to prepare themselves to meet the new requirements resulting from the authorisation" is allowable, owing to pre-existing premixtures which are still on the market. They will be allowable until such stocks are depleted.

Finding an alternative

The reduction of copper use is significant and has the potential, if not addressed, to have a negative impact on the industry in terms of pig growth rates, and pig farming yields and economics. Given copper’s proven benefits to gut health, it’s imperative that the industry is actively seeking an alternative to ensure that pig health is maintained.

The good news is that the industry has indeed been conducting research into nutritional alternatives for copper in post-weaning diets.

Dr Steve Jagger, senior pig nutritionist, ABN, and Tegan Sutton, developmental pig nutritionist, ABN, are working with the University of Leeds to understand the benefits of acidification in low copper diets on gut health and growth. The research examined the effect of acids on the performance of growing pigs, to see if it is possible to balance the impact of reducing copper with other supplements.

The results of this trial have found that there is a significant positive effect of the acids (Trt A & B) on final body weight, average daily gain, and feed conversion ratio (Table 1). Trt A & B increased the average daily gain by 56-58g/d, compared to control.

All of the diets were low in copper, proving that acids can replace the growth lost by its reduction.

While it is unlikely that there will be one simple solution, as an industry, significant progress has already been made. For example, the research above indicates that, in some cases, acid is able to deliver a similar level of performance in young pigs as achieved through higher copper levels by protecting the gut to reduce infection, showing that it is possible to offset a significant reduction in copper by adding acid to pig feed. As a result, ABN has already increased the acid level of their weaner feed.

It is clear that change is inevitable and although this level of change to piglet nutrition will create uncertainty, the industry and its leaders continue to actively seek solutions to ensure that pig health is maintained, and pig farmers’ margins and productivity are protected.

Further Reading

Emily Houghton is a Zoology graduate from Cardiff University. Emily has worked in livestock husbandry, and has written, conducted and assisted with research projects regarding the synthesis of welfare and productivity of free-range food species.